Modern flight deck displays for vehicles (such as aircraft or spacecraft) display a considerable amount of information, such as vehicle position, speed, altitude, attitude, navigation, target, and terrain information. In the case of an aircraft, most modern displays additionally display a flight plan from different views, either a lateral view, a vertical view, or a perspective view, which can be displayed individually or simultaneously on the same display.
The lateral view, generally known as a lateral map display, is basically a top-view of the flight plan, and may include, for example, a top-view aircraft symbol, waypoint symbols, line segments that interconnect the waypoint symbols, and range rings. The lateral map may also include various map features including, for example, weather information, terrain information, political boundaries, and navigation aids. The terrain information may include situational awareness (SA) terrain, as well as terrain cautions and warnings which, among other things, may indicate terrain that may obstruct the current flight path of the aircraft. The perspective view provides a three-dimensional view of the vehicle flight plan and may include one or more of the above-mentioned features that are displayed on the lateral map, including the terrain information. In this regard, some modern flight deck display systems incorporate a synthetic terrain display, which generally represents a virtual or computer simulated view of terrain rendered in a conformal manner.
The primary perspective view used in existing synthetic vision systems emulates a forward-looking cockpit viewpoint. Such a view is intuitive and provides helpful visual information to the pilot and crew. However, a forward-looking view has limitations in that it may not always display the intended approach target or object of interest. For example, if the aircraft is approaching from the side of the destination airport and the pilot needs to turn the aircraft a significant amount for runway alignment, then the airport or the target runway might be out of the synthetic field of view. In reality, the pilot would be able to keep his eye on the airport by turning his head and viewing the airport through a side window. Using a synthetic or virtual display, however, the airport will momentarily move off the screen. Lack of target focus in this manner can be confusing and frustrating for pilots.